Ocean wave energy is a field of great interest worldwide due to its renewable character, widespread availability and great potential as a future energy source. It is well known that ocean waves hold the highest energy density compared to other major renewable energy sources such as wind and solar energy. Over the years there has been a wide variety of attempts to harvest this energy in a reliable and economically viable manner. The objective is to convert the wave energy into a more useful energy form such as electricity.
Numerous wave energy conversion systems can be found based on varying technical principles. Some systems operate on the principle of an oscillating water column, exploiting the displacement of air due to the rise and fall of the water level. Other systems physically capture the water of an incoming wave in a reservoir and exploit the potential energy of the water as it returns to the sea. Yet other systems consist of bodies which movement is exited by the waves, and the movement relative to a point or body can be exploited. Wave energy conversion systems can be fixed to the shore, be situated near the shore, while others are located offshore.
One of the main challenges of all wave energy conversion systems is the energy conversion efficiency, which directly relates to the cost of generating power. If the efficiency is low and the cost per produced kWh electricity is too high, the technology cannot compete with power delivered from other energy sources.
A disadvantage of many existing wave energy converters is that they are optimized for a small range of wave amplitudes, wavelengths and frequencies and to one specific direction of the incoming waves. However, the irregular nature of ocean waves and changing conditions necessitates wave energy converters that are able to handle a large variety of wave parameters, in order to maintain a continuously high energy conversion efficiency, and thereby having a high profitability.
Another challenge with wave energy converters is that they often are installed offshore in a harsh environment exposed to corrosive salt water and extreme weather conditions. Designing structures for these severe conditions can be expensive and difficult, and existing wave energy converters often fail and break. Furthermore, their offshore location complicates and increases the costs of installation, maintenance and repair.
Hence, an improved wave energy conversion apparatus would be advantageous, and in particular, a wave energy conversion apparatus with a high energy conversion efficiency over a wide range of wave parameters adapted to exploit waves from multiple directions.